It took three nights to collect photons for my latest image: M16 the Eagle Nebula. The large number of sub-exposures in this image greatly helped in reducing the noise despite summer time temperatures.
This project started in May and was just recently finished. During July, the week around new moon it was continually forecast to be clear and consistently clouded up at night. None of the major forecasts, nor the ClearSky Clock were able to get the night sky forecast correct.
As with last year I tried the instant cold packs to try and keep the 350D camera cool. They were unable to last the entire 50 minute periods I was using. They did help somewhat as the nighttime temperature never dropped below 72 degrees F.